textproduct: Albany

WHAT HAS CHANGED

Increasing confidence for heat-related impacts Thursday and Friday in valley areas of eastern NY and western New England with the highest confidence of reaching heat advisory criteria (heat index 95F or higher) in the mid-Hudson Valley. Latest HeatRisk guidance shows minor to locally moderate heat-related impacts.

KEY MESSAGES

1) Chances for showers and thunderstorms increase Thursday and Friday, highest during the afternoon hours. Any storm can produce heavy downpours with a low chance for strong to severe storms.

2) Increasing confidence for heat-related impacts Thursday and Friday due to high humidity and warming temperatures. There is a low to medium chance that conditions will necessitate heat advisories in the mid-Hudson Valley.

DISCUSSION

KEY MESSAGE 1...

Very comfortable and pleasant conditions return today into tomorrow as high pressure builds over the Northeast. Then, a Bermuda high becomes anchored off the East Coast for the end of the week. Persistent southwesterly flow around its periphery will advect a warm and very humid air mass from the Gulf and western Atlantic into the Northeast with PWATs reaching 2 ST DEV above normal per the NAEFS and ranking above the 90th percentile of the CFSR climatology for early August.

A weak shortwave from the Southeast U.S becomes sheared out as it tracks within the southwest flow aloft into the Northeast with broad troughing becoming established over the Canadian Prairie and the Great Lakes. Southwest winds aloft strengthen as the Northeast is caught between the upstream troughing and Bermuda high off shore supporting increased deep layer shear. The moist air mass in the presence of at least some sunshine will easily contribute to moderate instability. Mid and upper level forcing is weak but there are signs of a sfc pressure trough tracking eastward off Lake Ontario which would provide a focus for sfc-based convection on Thursday. Therefore, expecting isolated to scattered showers and storms to develop during the traditional peak heating hours capable of producing heavy downpours. Shower/storm coverage will increase should the sfc trough push eastward. Favorable instability and sufficient deep layer shear increases the chance for strong/severe storms with the latest AI NWP Convective Hazard Forecast showing 15 - 30% chance for severe storms. Similar set- up for Friday but shower/storm coverage looks to increase as the upstream troughing and sfc boundary pushes eastward. These factors can also support a greater risk for severe weather with the AI NWP Convective Hazard Forecast showing 15-30% chance and even a narrow swath of 30-45%. Otherwise, WPC maintains a widespread marginal risk for excessive rainfall both days given potential for heavy downpours where soils are saturated from recent heavy rain.

KEY MESSAGE 2...

The combination of uncomfortable humidity levels and temperatures warming slightly above normal Thursday and Friday increases the risk for heat-related illness, especially in valley areas. Latest HeatRisk graphics show much of eastern NY and western New England reaching the minor category on Thursday with minor to moderate on Friday. Latest NBM probabilistic guidance shows a 40 to 60% chance for temperatures exceeding 85 degrees both days in valley areas with a 60 to 90% chance in the mid-Hudson Valley. There is even a 15 to 30% chance that the mid-Hudson Valley reaches or exceeds 90 degrees. There is a low to medium chance that these conditions will necessitate heat advisories with the highest chance in the mid-Hudson Valley. Plan to avoid strenuous outdoor activities both days, have a way to stay cool or access air conditioning and drink plenty of water, even if you are not thirsty.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

Through 12Z Wednesday...VFR conditions prevail across all terminals through at least 06 UTC Wednesday with generally light winds under 5kts and clear skies. There is low chance for fog to redevelop towards the end of the TAF period at GFL, ALB and POU as low-level moisture starts to increase again but not enough confidence to include in this TAF issuance.

Outlook...

Wednesday Night: Low Operational Impact. Chance of SHRA. Thursday: High Operational Impact. Definite SHRA...TSRA. Thursday Night: Moderate Operational Impact. Scattered SHRA...TSRA. Friday: High Operational Impact. Numerous SHRA...TSRA. Friday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Saturday: High Operational Impact. Likely SHRA...TSRA. Saturday Night: Low Operational Impact. Slight Chance of SHRA...TSRA. Sunday: Low Operational Impact. Slight Chance of SHRA...TSRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.